A nursing student is preparing to give a medication that has a boxed warning. The student asks the nurse what this means. What will the nurse explain about boxed warnings?

Choice A Reason:

Beta2 agonists, such as terbutaline, are commonly used to manage premature labor. These drugs work by stimulating beta2 adrenergic receptors in the smooth muscles of the uterus, leading to relaxation and suppression of contractions. Therefore, questioning the use of a beta2 agonist in this scenario would not be appropriate.

Choice B Reason:

Anticholinergic drugs are not typically used to manage premature labor. They work by blocking the action of acetylcholine in the nervous system, which can lead to various effects such as reduced secretions and relaxation of smooth muscles. However, they are not specifically indicated for stopping uterine contractions, so questioning their use in this context is less relevant.

Choice C Reason:

This is the correct answer. Beta2 antagonists, also known as beta-blockers, work by blocking beta2 adrenergic receptors, which can lead to increased uterine contractions. Using a beta2 antagonist in a patient experiencing premature labor would be counterproductive and could exacerbate the condition. Therefore, it is appropriate to question the use of beta2 antagonists in this scenario.

Choice D Reason:

Alpha1 agonists are not typically used in the management of premature labor. These drugs stimulate alpha1 adrenergic receptors, leading to vasoconstriction and increased blood pressure. They do not have a direct effect on uterine contractions, so questioning their use in this context is less relevant.

Choice A: Metabolic Acid Deficit (Metabolic Alkalosis)

Vomiting or continuous nasogastric suctioning leads to the loss of gastric contents, which are rich in hydrochloric acid (HCl)1. This loss results in a decrease in the body’s acid levels, leading to a condition known as metabolic alkalosis2. Metabolic alkalosis is characterized by an increase in blood pH due to the loss of hydrogen ions (H+) and an increase in bicarbonate (HCO3-) levels. This condition can cause symptoms such as muscle twitching, hand tremors, and light-headedness.

Choice B: Carbonic Acid Excess (Respiratory Acidosis)

Carbonic acid excess, or respiratory acidosis, occurs when there is an accumulation of carbon dioxide (CO2) in the blood, leading to a decrease in blood pH3. This condition is typically caused by respiratory issues such as hypoventilation, chronic obstructive pulmonary disease (COPD), or severe asthma. It is not directly related to vomiting or nasogastric suctioning, which primarily affect the metabolic component of acid-base balance.

Choice C: Metabolic Acid Excess (Metabolic Acidosis)

Metabolic acidosis is characterized by a decrease in blood pH due to an accumulation of metabolic acids or a loss of bicarbonate. Common causes include renal failure, diabetic ketoacidosis, and severe diarrhea. Vomiting or nasogastric suctioning, which result in the loss of gastric acid, do not lead to metabolic acidosis but rather to metabolic alkalosis.

Choice D: Carbonic Acid Deficit (Respiratory Alkalosis)

Respiratory alkalosis occurs when there is a decrease in carbon dioxide levels in the blood, leading to an increase in blood pH. This condition is often caused by hyperventilation due to anxiety, fever, or high altitude. It is not related to the loss of gastric contents through vomiting or nasogastric suctioning, which primarily affect the metabolic component of acid-base balance.